The Journey of a Diamond

Diamond cutting is such an intricate craft it is often described as an art form. Below is an explanation about how they evolve from a rough stone into one of the many beautiful pieces we have in our current stock here at Cuttings.
 

How are diamonds formed?

Diamonds form 100 miles underground, under the pressure of tremendous heat. In these conditions, carbon crystallises into a rough stone. Through a volcanic eruption, known as a kimberlite eruption, the rough diamond reaches the earth’s surface. Specialists believe the last of such an eruption took place 100 million years ago.
 

How are diamonds mined?

The diamonds which sit closer to the earth’s surface can be excavated. Some geologists use termites to find kimberlite pipes because, in the process of building their mounds, termites sometimes dig up rocks and minerals that expose diamonds below.

Pit-mining is the most common way of recovering diamonds from kimberlite pipes. There are two ways it can be done: open-pit or underground.

Open-pit mining is only used when diamonds are near the surface or under thin layers of gravel or sand. This process is easily done but underground mining is much more complicated. The method used to mine underground is dependent on the following variables: nature, shape and size of the kimberlite deposit.

Searching for diamonds in the seabed requires a different process: horizontal and vertical marine mining. In horizontal mining, a miner uses a flexible hose on the ocean floor to bring the stones to the surface. In vertical mining, on the other hand, a large drill brings any diamond bearing gravel to the surface.

Lastly, alluvial mining is a natural way of discovering diamonds. Through this process, diamonds reach their present resting place after being carried by the wind, and water down rivers over the course of millions of years.  
 

How are Diamonds shaped?

Once the diamonds have been mined they are shaped using these four basic techniques.

1. Cleaving:

Cleaving is done to make the diamond a manageable size. The diamond is cleaved where the diamond is weakest, which is the tetrahedral plane. The diamond is kept in place with a wax or cement mould. Following that, the cutter strikes groove along the plane, then it places a steel blade into this groove, cutting the rough diamond in half.   

2. Sawing:

At times, a diamond has to be cut where there is no plane of weakness, which cannot be done through cleaving. Instead, the diamond is sawed with a phosphor-bronze blade, or alternatively a laser. While sawing, the cutter determines what will be the ‘table’ (the flat top of the stone) and the ‘girdle’ (the rim of the stone at the point of largest diameter). Once this process is complete the diamond can be cut.

3. Cutting/ bruiting (cutting a diamond by hand):

Through this process, the diamond takes its final shape. Diamonds are cut by using other diamonds; making use of the stone’s hardness. Through the mechanical process, the diamond is placed in a lathe, and another diamond in the lathe rubs against it to create the rough finish of the girdle.

4. Polish:

To finalise the process, the diamond is placed above a rotating polishing wheel. The wheel is coated with an abrasive diamond powder which smooths the stone when they come into contact.
Following this, the ring is set, which can be done through a number of different techniques, but we will explore this in another article. 
 

To see the diamonds that we have available at Cuttings, check out our current stock, or visit us in person at our Margate branch. We’d love to be of service.